The first thing you’ll notice about these new 2500/3500 pickups is that they share the exterior redesign of the Silverado and Sierra 1500. As we detailed in a past report, though the design of the new trucks looks bigger, it’s actually a lot more aerodynamic. That’ll come in handy with fuel economy and while towing. GM says the exterior also improves on cooling which helps in providing more consistent engine power under tough conditions.

Three powertrains will be available for both the Silverado HD and Sierra HD. The base package is a 6-liter Vortec V-8 with a six-speed transmission delivering 360 horsepower and 380 lb.-ft. of torque on the 2500. A version rated at 322 horsepower is standard for the 3500. The second package is a bi-fuel version of the Vortec V-8 that accepts gasoline and compressed natural gas (CNG).

The third package pairs the Duramax 6.6-liter turbodiesel with an Allison 1000 six-speed transmission. This combination is rated at 397 horsepower and 765 lb.-ft. of torque.

GM says the new models boast payload improvements over their predecessors. Maximum available payload is now 7,374 pounds, up from 7,222. Maximum available conventional towing is now 19,6000 pounds, up from 18,000 and max fifth-wheel towing is up to 23,200 pounds from 22,500. GM says each of these ratings is best in class.